Vacuum type mixer



y 30, 0- A. K. BRENNAN ET AL VACUUM TYPE MIXER Filed April 12, 1959 s Sheets-Shee t 1 July 30, 1 A. K. BRENNAN ET AL VACUUM TYPE MIXER Filed April 12, 1939 3 Sheets-Sheet 2 [J d JHi-HU E 4 I W A/ 1 I l 1 I I 1|L1|| w I Kl 5 n h /W N u 6 w W fi July 30, 1940.

VACUUM TYPE MIXER Filed April 12, 1959 3 Sheets-Sheet 5 A. K. BRENNAN ET AL 2,209,559

Patentecl July 30, 1940 PATENT OFFICE VACUUM TYPE MIXER Ambrose K. Brennan and James M. Jans, York,

Pa., assigncrs to Read Machinery Company, I Incorporated, York, -Pa., a. corporation of 1 Pennsylvania Application April 12, 1939, Serial No. 267,504

4 Claims.

This invention relates to mixers and more particularly to mixers in which the mixing operation is conducted under a partial vacuum".

An important object of our invention is 'to' 3 provide a mixerbf the vacuum type which is so constructed as to prevent lub-ricantor other foreign matter fromentering the mixing re ceptacle, and thus contaminating the material beingmixed,,through the clearance space betweenthe agitator shafts and the openings inthe end walls of the receptacle through which they extend. More particularly this object 152668111- plished by the provision of vacuum compartment's'contiguous to' the end walls. of the mixing receptacle (one or both of which compartments may include a gear case for housing the driving mechanism) and by locating the shaft bearings exteriorly of and spaced from the end walls of the Vacuum compartments. In the preferred form of the invention, the clearances surr'ound ing the shafts will be closed by sealing members held in tight'engagemen't with the end walls of the receptacle.

Another object of our invention is to provide inian apparatus of the above character a unitary hinged cover for closing the tops of the mixing receptacle andvacuum compartments so that by raising the cover access is afforded to both the receptacle and compartments.

In order to compensate for wear between the cover and the top of the mixer, the invention has for a further object to provide means Whereby the center of pivotal movement of the cover may be adjusted so that the cover will seat" flatly and tightly against the top of the receptacle and compartments.

The invention has as still another object to provide in a mixer of the above character ports inthe cover extending between the mixing re ceptacle and'the vacuum compartments whereby the receptacle and compartments, including the gear case, may be placed under a partial vacuum by an exhauster operatively connected through the cover with the receptacle. In the preferred form of the invention, a valve isprovided for closing communication between the receptacle and compartments after an initial's-hort period of operation of the apparatus and after a balanced sub-atmospheric condition has been attained in order to prevent vapors from the mixing receptacle from entering and condensing within the vacuum compartments.

Other objects and advantages will be apparent from the following detailed descriptionof a preferred embodiment of the invention, reference being had to the annexed drawings in which:

Figure 1 is a View in front elevation of a mixer of the vacuum type; I

Figure 2' is an end-elevational View of the Figure S is a detail view, in part cross-sectional, taken on the line 2' 2 of Fig. 2, and showing a vacuum compartment and aishaft seal adjacent one end of the mixing receptacle;

Figure 4 is a detail View of the pivotal connection of the'coverclosing the top of the mixer, certain parts thereof being shown in cross-- section;

Figure 5' is a vertical cross-sectional view' through a vacuum compartment showing a shaft seal; and

Figure 6 is new" on the'line 6 6 of Fig. 5

showing the sealing "ring "and spring-biased lever fo-r'iholdin'gf-the' sealing ring in place:

"'Re'ferring'io' the drawings, the mixer illustrated therein comprises a mixingreceptacle I provided at its'oppo'siteends with vacuum compartments 2 located exteriorly of'the end walls 3of the'receptacle. Themixer is of the doubletrough type in'which a pair of agiators 4 and 4a, arranged" inp'arallelrotate within a pair of arcuate bottoms "5,'indicated by-dotted lines in Fig. 2. The mixing receptacle is enclosed along itsbottom and sides; by a jacket 6 (Fig; 3)

through" which a'heating' or cooling medium is circulated in any-suitable manner.- "A dome-shaped cover I, provided with glassv windows 'la'for viewing the interior of the mixing chamber, is integrally connected by an arched v haust fan or pump, not shown, which maintains casting forms the end wall 3 of themixing receptacle while the other end of the casting constitutes the outer end wall l2 of the vacuum compartment. Adjacent its bottom the casting la forming the vacuum compartment is longitudinally extended to provide a gear case 3a beyond the end Wall 12. An opening l2a affords communication between the portions of the vacuum compartment lying upon opposite sides of the end wall [2. The outer end of the gear case is closed by an end plate 13.

The agitators 4 and 4a are supported at their corresponding ends by shafts 4b and 40 which extend through aligned openings in the end walls 3 and I2, and in the end plate l3. Anti-friction bearings II and Ila respectively are securely mounted in the end wall [2 of the vacuum compartment for supporting the: shafts 4b and 4c. Shaft 41) extends through a lubricated packing gland l5 in the end plate I3 and is supported at its end exteriorly of the mixer in a bearing l5 mounted on a pillar l'l. Shaft 40 is supported in addition to the bearing Ha in an anti-friction bearing I I mounted in the end plate l3 and this shaft terminates in a reduced section 4d which projects through a packing gland 14 in the end plate. 7

The vacuum compartment 2 at the opposite end of the mixer is similarly constructed, it being understood that agitator shafts corresponding to shafts 4b and 4c are supported in bearings arranged in the end plate plate of the vacuum compartment. These end plates [3 at opposite ends of the mixer are provided with trunnions 4'1 concentric with the companion shafts 4b, and these trunnions rest in bearings lfia and b mounted on columns Ila and llb, respectively, to permit tipping the mixer.

Power is transmitted to the agitator 4 by means of a chain belt l8 (Fig. 2) extending between a sprocket l9 and a larger sprocket l9a keyed to one end of the shaft 42). Sprocket I9 is driven by an electric motor M either directly or through a suitable speed reduction mechanism. Within a the gear case 3a, as indicated in Fig. 3, is housed l to shaft 4b as indicated in the drawings. 70

a pinion 20 keyed to shaft 4b meshing with a companion pinion 2| secured to shaft 40. .In

' this way both agitators are driven from the motor M. e To tip the mixer on trunnions 4'! to discharge its contents a worm sector 22 attached to end plate l3 at one end of the apparatus is rotated by a Worm 23 suitably driven from a motor M, through a gear train 230.. Thus when rotation is imparted to the worm 23 the mixer rocks Within the bearings 16a and l6b.

For controlling the temperature of the material being mixed in addition to the control furnished by the medium in the jacket 6, the agitators and shafts are cored throughout their length as indicated at 21 in Fig. 3. During operation of the mixer a heating or cooling medium from any suitable source is circulated through the agitators from an inlet pipe 28 coupled to an end of shaft 40. At the opposite end of the mixer the shafts are connected by a return bend pipe 28a in such manner that the heating or cooling medium after passing through the agitator 4a is returned through agitator 4 to an offtake pipe 29 coupled If desired, the agitators may be connected in parallel for the circulation of the heating or cooling medium instead of in series as just described.

The clearances between the shafts 4b and 4c g; and the openings in their companion end walls 3 of the mixing receptacle through which they extend into the vacuum compartments are closed as illustrated more particularly in Fig. 5. In this figure the structure for closing the clearance about shaft 4b is shown, although it is to be understood that each of the shafts 4b and at, at opposite ends of the mixer, is provided with similar sealing means. I

Bolted to the end Wall 3 inside the mixing chamber and surrounding the shaft 4b is a closure plate 30. This closure plate is provided with a beveled inner circumference 30a disposed adjacent the shaft and expanding toward the vacuum compartment and with a circular groove 3% formed within its rear face. A sealing member is adapted to cooperate with this closure plate and to seal the clearance between the inner circumference of the closure plate and the outer circumference of the shaft. The sealing member comprises a sealing ring 3| located within the vacuum compartment and surrounding the shaft 4b. Aifixed to the face of the sealing ring dis posed toward the closure plate 30, is a transversely split collar 32, the two sections of which are detachably connected to the sealing ring by means of a series of headed pins 32a on the collar extending into companion keyhole slots 32b formed in the sealing ring.

To the collar 32 is fastened a transversely split packing ring 33 by screws 33a, this packing ring preferably being made of a flexible composition. The outer face of the packing ring is channeled to produce a lip 331) which bears against the beveled edge 30a of the closure plate 30 and being thereby forced into contact with the circum ference of the shaft 4b.

For yieldingly urging the sealing ring and its associated parts into closing relationship with reference to the clearance surrounding the shaft 4b, a lever 34 is provided. This lever is pivoted intermediate its ends in a bracket 35 upon the end wall 3 of the mixing receptacle. The lower end of the lever is forked so as to bridge shaft 41) and each branch of the fork is slotted so as to fit over a pin 3Ia provided by each of a pair of ears on the sealing ring 3|. The upper end of the lever is urged by a coil spring 36, connected to the end Wall I2 of the vacuum compartment, in a direction such as to rock the lever about its pivotal support in bracket 35 and force the sealing ring into contact with the closure plate 30, and to consequently cause the beveled edge of the sealing plate to deflect the lip 33b of the packing ring into tight engagement with the shaft 4b. The upper end of the lever is twisted at right angles and slotted so as to straddle an eyebolt 31, which eyebolt in turn is threaded into a nut 31a engaging a face of the lever.

By virtue of the above construction the pressure exerted upon the sealing plate may be varied by simply rotating the nut 31a to move the eyebolt inwardly or outwardly of the nut thereby changing the tension of the coil spring 36. When it is desired to remove the packing ring for cleaning or renewal, it is only necessary to detach the lever 34 from the eyebolt 31 and then lift the lever from the bracket 35 and out of the vacuum compartment. The sealing ring 3| is then slid along the shaft 4b and by rotating the collar 32 and packing ring 33 relative thereto until the heads of pins 32a register with the enlarged portions of the keyhole slots 32b, the two half-sections of the combinedcollar and packing ring may be separated to permit their removal drawing the screws 33a) for'cleaning or renewal of the packingring.

The parts are assembled by simply reversing the-order of the above steps. Each of theopenings throughwhich the shafts 4b and 4c pass into the vacuum compartments at opposite ends of the mixer are provided with sealing means as just described.

The dome-shaped cover 1 is adapted to .seat flatly on a packing strip 33 surrounding the top of the mixing receptacle and vacuum compartments. The interior of the cover is provided with vertical webs 39 (Fig. 1) designed when the cover is closed to abut the tops of. the end walls 3 of the mixing receptacle andthus close communication between the mixing chamber and the vacuum compartments. Intercommunication between each vacuum compartment and the mixling chamber is afiorcled by a connector tube at of inverted U -shape mounted on the cover and bridgingeach web 39. Each connector tube has associated therewith a valve V so as to permit opening and closing communication between the vacuum compartment and the mixing receptacle.

For insuring "that the coverwill always make flat contact with the top of the mixing receptacle and vacuum compartments, the axis of pivotal movement of the cover may be adjusted ripwardly or downwardly to compensate for any wear. The cover '5 as has previously been stated is supported by the arched neck 8 which is integral with a hollow sleeve 9. The means by which the hollow shaft is supported in the post H3 is indicated in Fig. 4. The post i rovider: pair of vertical arms Ilia and IE1) at its upper end between which is received the hollow sleeve 9. This sleeve is of generally cylindrical shape is formed with end walls to and 9b. Bolted to end wall 9a is a circular plate M from which a stub shaft 52 projects axially outward. Similarly a circular plate 43 having an axial stub shaft 44 is bolted to the other end wall 91) of the sleeve. The stub shafts 42 and 44 thus project axially in opposite directions from the sleeve and are received respectively in openings provided in the arms Km and Nib of the post 10.

The circular plate 43 and stub shaft 44 are bored so as to provide a central passageway Ma extending throughout the length of this plate and stub shaft which passageway communicates through an opening 4-5 provided in the end wall In with the hollow interior of the sleeve 9. Beyond the arm lGb the stub shaft 4d communicates through a slip connection 46 with a conduit E leading to an exhaust fan or pump. The stub shaft 42 is of solid construction and is re ceived in an opening in arm lfla, the portion of the shaft projecting beyond the arm having a counterweight 48 fastened thereto.

Surrounding and providing bearings for the stub shafts 42 and M are eccentric bearing rings 49 and These eccentric rings are of the same size and eccentricity so that by angularly adjustlng these rings within their arms the axis of rotation of the sleeve 5, and hence of the cover I. may be raised or lowered a limited distance.

For raising the cover a hand wheel 50 is mounted at the forward side of the mixer on one end of horizontal shaft 51 which shaft is supported for rotation in the machine frame and carries at its other end a self-locking worm 52 (see Fig. 2). This worm meshes with a worm wheel 53 on a second horizontal shaft 54 extending longitudinally and to the rear of the mixer. Secured to shaft 54 is a sprocket 55 (see Fig. 1) and between this'sprocketaandia companion sprocket 55 keyed to stub shaft'di'yrunspa chain 5'1. An idler roller 53 may be suitably mounted on the, post Ill to take up slack in the chain. Thus by turning the handwheel 5d the cover? may be readily raised or lowered. When the machine is in operation the cover is latched tightly in place by hooks 52! pivoted to the-.cover and adapted to swing into and out of locking" engagement with lugs 6!) on the mixing receptacle. I

From the foregoing description it will be apthat during operation of the mixer gases will. be. continuously exhausted from the mixing: receptacle land, through the connector tubes All, from the. vacuum compartments 2 to maintain a sub-atmospheric pressure therein. Because of the spacing of the bearings i! and lid for the shafts ib. and do away from the end walls 3 of the mixing receptacle, and because of the. bal

anced low pressure between the mixing chamber and the vacuum compartments there is no tendency forthe oilor grease required for lubrication of the bearingstobesucked intothe mixing chamber. Furthermore, any oil or dirt which may find its way into. the vacuum compartments is prevented from entering the mixing. chamber by reason of the sealing members ill which are wedged into the clearance spaces surrounding the shafts to and 4c.

-Because of the possibility that vapors from the mixing chamber may migrate by way of the connectar tubes luinto the. vacuum compartments and condense therein itis undesirable to maintain; the connector tubes-iii open except during the initial stage .of operation'of-themixer. .Such condensate. imparts'an unsightly and unsanitary appearance to the mixer and in some instances the vacuum to be maintained in the vacuum.

compartments throughout the run. The mannor of removing the sealing members for cleaning or replacement has already been described. I

When it is desired to empty the contents of the mixer, the hand wheel '50 is rotated to raise the cover 1 and the mixer is then tilted upon its trunnions 41 in bearings i611 and lfib by connecting the worm 23 to a source of power M, as has previously been explained.

Should the cover be found not to seat tightly against the top of the mixing receptacle and the vacuum compartments because of wear upon the packing strip 38, the eccentric rings 49 and 49a may be'angularly adjusted within the arms Mia and lUb of post Ill so that the axis of oscillation of the sleeve 9, and hence of the plane of the contacting surface of the cover with the mixer, is raised or lowered so that the cover bears solidly upon the packing strip.

The invention may be embodied in other specific forms without departing from the spirit or essential characteristics of the invention, and the present embodiment is therefore to be considered as illustrative and not restrictive, and all changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein.

We claim:

1. A vacuum type mixer comprising a fluidtight mixing receptacle having closed side and end walls, fluid-tight vacuum compartments contiguous to the end walls of the receptacle, means for closing the tops of the receptacle and compartments, a passageway for exhausting gases from the receptacle, a passage between the receptacle and each compartment through which gases are exhausted from the compartment, means for opening and closing the passage, an agitator in the receptacle having shafts extended through the end walls of the receptacle into the compartments and bearings supporting the shafts located externally of the receptacle and spaced from its end walls.

2. A vacuum type mixer comprising a fluidtight mixing receptacle having closed side and end walls, fluid-tight vacuum compartments contiguous to the end Walls of the receptacle, a unitary cover closing the tops of the receptacle and compartments and affording access thereto, a passageway for exhausting gases from the receptacle, connector tubes on the cover bridging the end walls and providing communication between the receptacle and the compartments through which gases are exhausted from the compartments, a valve for opening and closing the connector tubes, an agitator in the receptacle having shafts extended through the end walls of the receptacle into the compartments and bearings supporting the shafts located externally of the receptacle and spaced from its end walls.

3. A vacuum type mixer comprising a fluidtight mixing receptacle having closed side and end walls, fluid-tight vacuum compartments contiguous to the end walls of the receptacle, a unitary removable cover for closing the tops of the receptacle and compartments, a passageway for exhausting gases from the receptacle, a passage between'the receptacle and each compartment through which gases are exhausted from the compartment, means for opening and closing the passage, an agitator in the receptacle having shafts extended through the end walls of the receptacle into the compartments and bearings supporting the shafts located externally of the receptacle and spaced from its end walls.

4. A vacuum type mixer comprising a fluidtight mixing receptacle having closed side and end walls, fluid-tight vacuum compartments contiguous to the end walls of the receptacle, a unitary hinged cover for closing the tops of the receptacle and compartments, a passageway opening through the cover for exhausting gases from the receptacle, a passage between the receptacle and each compartment through which gases are exhausted from the compartment, a valve for opening'and closing the passage, an agitator in the receptacle having shafts extended through the end walls of the receptacle into the compartments and bearing supporting the shafts located externally of the receptacle and spaced from its end walls.

AMBROSE K. BRENNAN. JAMES M. JANS. 

